I have a NFT / Ebb system. The plants at the end of my pipe are near the drain. I know the roots are going to go into the drain and possibly plug the drain. This is the nft drain. The over flow drain for the ebb partis higher and dry most of the time so that wont get root bound.

Is there anything that can prevent roots from growing into the drain?

I do allot of DIY stuff for my gear and a quick thought on your problem gets me thinking about possiblly pantyhose covering the drain or maybe an aquarium fish net over the drain? What size hole and material you working with?

I would think roots would grow right through pantyhose or fishnet easily since it can grow through rockwool or even coco real easily. probably would plug it faster since now instead of one drain hole you got thousands that can easily be pluged by your roots

To prevent drain clogs, I employ a few simple methods in ebb and flow systems:
1. Make your bottom drain fitting the pump outlet. This has the benefit of cleaning your drain screen and forcing growing roots back into the tray every fill cycle.
2. Keep the drain dry as much as possible. When the tray isn't draining, your drain should be dry. If you want a little water to remain in your tray, just install it slightly above the bottom of the tray.
3. Make the drain pipe a large diameter. There is a reason sinks and bathtubs have large drain holes.
4. Put a coarse screen that you can remove easily over the drain outlet. If the roots grow into the drain, simply remove the screen, cut the roots short, and replace the screen. If you have doubts about cutting roots, just move them far away from the screen and hope they won't find their way back in.
As you can see, my approach is one of improving the system design rather than applying patches. It's a pita at first, but once you work the bugs out, the effect is permanent. That way you don't spend your time maintaining bugs in your system and you have more time to focus on your growing. And then you can brag about what you did and how much better your system works.

a friend rolls a piece of copper screen and inserts it in the top of the drain line

the roots hit this and turn away from it